Caption: Anti hay-fever spectacles. A young woman wearing "Airshield" anti hay-fever spectacles in a field of oil-seed rape. The frames of these spectacles contain tiny air vents that maintain a cushion of filtered air behind the lenses, stopping pollen from settling on the eyes and thus preventing the allergic reaction that occurs in hay fever. The air is supplied by the small, battery- powered pump, about the size of a Walkman, which can be clipped to a belt or carried in a pocket. The spectacles provide an effective alternative to antihistamine drugs, which cause side-effects like drowsiness. They are also said to prevent tears when peeling onions.